Variable Geo (ヴァリアブル・ジオ), also known as V.G., is a Japanese 2Dfighting game / eroge series developed and published by Giga for home computers. It was also developed and published by Technical Group Laboratory (TGL) for home game consoles. It focuses on an all-female martial arts competition where participants are required to promote various family restaurants by acting as waitresses when not fighting.

Similar in many respects to other fighting games of the day, gameplay in Variable Geo utilizes a four-button layout, with two buttons each for punches and kicks of differing strength and speed. Special moves are initiated by keying in various movements using the control pad or joystick and punctuated with the press of one of the punch or kick buttons.

Following the trend of other fighting games such as Street Fighter and The King of Fighters series, as well as Ningyou Tsukai, later games would add a special meter that would fill as the player inflicts or receives damage. Filling the bar would result in a stock of "Energy" being acquired, which could either be used for one of a number of enhanced super special attacks, or saved for later use in the match. Some moves also require more than one Special Stock to be acquired before being able to use them.

Both characters begin any given fight with a full health bar that is depleted as they take damage from attacks. The first character to have her health completely depleted is the loser. In a single player game, defeating a CPU-controlled character yields a reward, showcasing the defeated character in an imaginary situation where she is either forced to commit an embarrassing (usually sexual) act in public or private, or is raped by an unseen assailant or assailants.

Set in a near-future version of Japan, the games tell the story of a martial arts tournament created to determine the country's strongest woman. The tournaments are sponsored by a number of family restaurants, who in exchange for their sponsorship, are given promotion in the form of having a tournament entry work as a waitress. As a result of the popularity of the tournaments, the restaurants experience a boom in patronage.

The winner of the tournament is awarded the title "Virgin Goddess", as well as a large cash prize of ten billion yen, and a house erected anywhere on the planet they should choose. However, when a given waitress is defeated, they are required to publicly strip themselves of their clothing (self-fondling and public masturbation may be forced upon the loser, and in the most extreme cases, the loser is raped/gang-raped, either in private or in front of an audience), in order to teach the so-called "true" shame of defeat. In spite of such humiliation, the tournaments often draw many competitors, each placing their pride and their dreams on the line as they battle for the top.

The first game in the series largely ignored a major storyline in favor of focusing more on the fighting system and hentai sequences. Players take control of one of six V.G. waitresses and battle the other five in order to win the tournament. Kaori Yanase and Reimi Jahana serve as the game's sub and final boss characters respectively unless the player is controlling one of them, in which case Yuka takes the place of the player-controlled character.

An updated version of the first game which adds three new playable characters, a storyline which features Yuka as the main character (who has a clone), and includes a pair of "True" bosses, the genetically engineered "Hybrid" warriors K-1 and K-2. The TurboGrafx-CD version was also released in the United States in September 1994 and was the only game in the series released in America. This game would later be re-released on the Sega Saturn and PlayStation with updated graphics and sound. The only major difference between the two versions is that the Saturn version retains the "Graphic Mode" setting which allows the viewing of the hentai scenes. This option was omitted from the PlayStation version.

V.G. II: Bout of Cabalistic Goddess (PC9800, Giga, November 25, 1994)

Kotoe Kashima, a childhood rival of Reimi, creates her own V.G. tournament in order to prove once and for all that she is far stronger and more beautiful than the Jahana Heiress. All of the previous fighters return and must face each other through a series of bouts. After defeating the other characters, the player must then face Kotoe's bodyguards before fighting Kotoe herself in a final match. This game was later declared non-canon by TGL.

The sequel to Advanced V.G. centers around a plot-driven "Story Mode" which features new protagonist Tamao Mitsurugi facing all of the previous competitors, as well as new faces Kyoko Kirishima and Saki Shinjou before going on to face the new boss characters Material and Miranda Jahana, Reimi's mother.

Another remake of Advanced V.G., this game features the same cast as Super V.G., but includes the same style of graphics and sound used in Advanced V.G. 2, along with reusing all Humiliation sequences from V.G. II: Bout of Cabalistic Goddess (though the dialogue was changed) and (non-canon) endings. Tamao Mitsurugi is a hidden character in the game and playable in versus and practice modes once unlocked.

V.G. Max (PC, Giga, September 10, 1999)

A game in which the V.G. waitresses are rendered as super deformed style characters akin to Pocket Fighter. Includes the original six V.G. contestants, as well as Satomi Yajima from Advanced V.G., Tamao Mitsurugi from Advanced V.G. 2, Yumiko Watanuki from V.G. II and new character Masako Houjouin.

V.G. Adventure (PC, Giga, March 17, 2000)

A text-based adventure game featuring the V.G. waitresses. The player takes control of Tamao Mitsurugi as she attempts to locate the missing Yuka Takeuchi and foil Miranda's latest plot. Fights are executed in a rock-paper-scissors fashion. With each successful attack, energy is added to a super meter that appears under the fighter's lifebar. Once full, the fighter can unleash a powerfully (in most characters' cases) unblockable attack. While Tamao is the only playable character in the storymode, there is a CPU versus mode that allows the player to pick from any character in the game.

V.G. Rebirth (PC, Giga, September 28, 2001)

A visual novel game in which the player plays the part of a reporter working on a story about the V.G. competition. The game also introduces the new character Hiyori Sakuragi. Depending on the choices the player makes, he/she will be paired with Yuka, Tamao or Reimi.

V.G. Rebirth Dash (PC, Giga, March 23, 2002)

An update to V.G. Rebirth which includes nearly every other non-boss character (Ayako Yuuki is absent as she is a lesbian) as an option to pair with the player. It also introduces the new character Keiko Hatano.

Yuka Takeuchi (武内 優香,Takeuchi Yuka) is a practitioner of karate who resides in Tokyo. After her parents died when she was young, her grandfather took her in and trained her in the martial arts, including Karate and the manipulation of ki energy. She enters the VG tournaments simply for the purpose of furthering her training and testing herself against strong opponents. Her virtuous, outgoing personality wins her many friends among the other fighters, among whom are Chiho Masuda, Jun Kubota, and Satomi Yajima, the latter of whom she has been best friends with for years. Apart of the main series, Yuka also appears in V. G. Neo as "Misty" and in Giga's crossover game Otome Crisis.

Chiho Masuda (増田 千穂,Masuda Chiho) is a trained ninja and was once the heir apparent to her family's ninja clan. However, she desires a life of freedom and happiness and thus has run away, becoming a "Missing-nin." She participates in hopes of using the prize money and free real estate to finance her new life.

Jun Kubota (久保田 潤,Kubota Jun) a wrestler with vast amounts of strength, Jun once participated in the Olympics while in high school. However, she was ejected from the games due to repeated unsportsmanlike conduct. She later joins the V.G. competitions because she can treat her opponents as roughly as she pleases. Despite this however, Jun operates by her own personal honor code. She fiercely believes that the use of weaponry in a martial arts bout is unacceptable.

Manami Kusunoki (楠 真奈美,Kusunoki Manami) is the youngest competitor in the VG Tournament at age 16. Along with her relative youth, she is also woefully immature, often acting like a girl half her age. Despite this however, she is a surprisingly clever and capable fighter, incorporating the natural energeticness of a child, as well her own vivid imagination into her fighting style. Her reason for entering the competitions is solely to obtain the large cash prize awarded to the winner. She is often the most lighthearted competitor in any given tournament, treating the fights as if they were all a big game.

Kaori Yanase (梁瀬 かおり,Yanase Kaori) is a 19-year old computer technician schooled in the art of Tae Kwon Do. She initially entered the V.G. tournament to test her own abilities, but found herself humiliated in the final round by Reimi Jahana. Ever since, she has devoted her training to defeating the multi-time V.G. champion. Despite this, Kaori apparently bears no ill will towards her would-be rival and simply sees defeating her as part of the path she must travel to become stronger.

Reimi Jahana (レイミ・謝花,Reimi Jahana) is the head of the Jahana Group, the organization which supervises the V.G. tournaments. Reimi is wealthy, highly intelligent, and extremely beautiful. She is also a skilled martial artist and a three-time V.G. champion. Reimi initially sees the competitions as a chance to prove herself the strongest and most beautiful warrior of all, and takes a kind of perverse pleasure in watching those who lose against her be humiliated in various ways. After being defeated by Yuka, she reforms and re-enters the tournament with the hopes of regaining her title.

Satomi Yajima (八島 聡美,Yajima Satomi) is a young woman who lives with her younger brother, Daisuke. their parents died when they're young. She earns money for living expenses and school tuition by working part-time jobs while caring for Daisuke. While she is an honest, straightforward person, she is also practical and realistic when it comes to situations involving money. This is because they have no other living relatives to provide for them, Satomi is often forced to take various odd jobs simply in order to make ends meet.

Ayako Yuuki (結城 綾子,Yūki Ayako) is the star attraction of the SoTO, a techno/rave dance club and restaurant, where she dazzles visitors with her flashy dancing. While appearing on the surface to be nothing more than a good-looking "Party girl", Ayako spends a great deal of her free time providing volunteer services to the needy and homeless. She also makes a pastime of luring out rapists, muggers, and stalkers and then beating them to within an inch of their lives, because they do unjust things to women.

Erina Goldsmith (エリナ・ゴールドスミス,Erina Gorudosumissu), also known as Elirin, is a full-blooded American born and raised in Osaka. She is loud, outspoken, and fond of bawdy humor. She owns and operates her own restaurant, The Rival, and fights in the V.G. tournaments in hopes of bringing her paternal grandmother from the United States to live with her in Japan. Erina practices no particular martial art, but instead fights using improvised methods derived from years of street brawling which she took up to vent her anger at her treatment by others due to a kind of prejudice commonly shown by Japanese towards foreigners.

Tamao Mitsurugi (御剣 珠緒,Mitsurugi Tamao) is a young girl who dreams of one day being like her idol, Yuka Takeuchi. To that end, she has tirelessly spent her spare time practicing amateur Karate and attempting to copy Yuka's various techniques. She somehow gained the ability to control her energy before her fourteenth birthday. Much like Yuka, Tamao is hard working, honest, and generally outgoing, which allows her to make friends easily. However, she is clumsy, forgetful, and tends to act before thinking things through.

Kyouko Kirishima (霧島 恭子,Kirishima Kyōko) is a member of one of the Masuda clan's branch families and Chiho's distant cousin. She is sent to compete under orders to either force Chiho back into the clan or kill her.

Yumiko Watanuki (綿貫 弓子,Watanuki Yumiko) : The first of Kotoe's bodyguards who specializes in Chinese martial arts. She would later reappear as a playable character in V.G. Max.

Terumi Kannazuki (神無月 輝美,Kannazuki Terumi): The second of Kotoe's bodyguards. She uses Muay Thai and treats Yumiko as if she were her younger sister.

Kotoe Kashima (嘉島 琴荏,Kashima Kotoe): A childhood rival of Reimi. She organizes the Bout of Cabalistic Goddess tournament in order to prove that she is superior to Reimi in every way. Extremely vain and antagonistic.

False Yuka: A clone of Yuka. She has more powerful versions of all of Yuka's own techniques.

Keiichi Sonezaki (曾根崎 啓一,Sonezaki Keīchi) / K-1 (Keiichi): The first model of Miranda Jahana's "Hybrids", genetically engineered supersoldiers. He has the distinction of being the only male to appear in a combat role in any V.G. game.

Kei Sonezaki (曾根崎 恵,Sonezaki Kei) / K-2 (ケーツー,Kētsū)* : The second model of Hybrid sent to attack anyone who could prove more powerful than Reimi. She and her brother were killed after being defeated by Yuka.

(Note: False Yuka only appears in the original Turbo CD version of the game. K-1 and K-2 take her place as the final bosses of all subsequent versions.)

Saki Shinjou (新条 サキ,Shinjō Saki): A sadistic, cold-blooded killer who fights for the sake of her own bloodlust. She competes in the V.G. tournament after being hired by Miranda. She also has an unexplained grudge against Reimi and frequently expresses a desire to kill her.

Material (マテリアル,Materiaru): The latest model of Hybrid designed by Miranda. There are two of these units, and both are programmed to express no emotions of their own since Miranda believed emotions to have been the ultimate downfall of the K-series. Both are defeated separately by Yuka and Tamao and die.

Miranda Jahana (ミランダ・謝華): Reimi's mother and the true head of the Jahana Group, which supervises the V.G. tournaments. She had hoped to create the ultimate fighting machine using data collected from the fighters in her tournaments. After the Material units are disabled, she engages Yuka, who is able to match her in strength. After being somewhat weakened by this exchange, she is attacked by Tamao, who is barely able to defeat her. Following this, she is caught in a combined attack by both Yuka and Tamao and is presumed dead, although she makes a cameo appearance in a background in V.G. Max.

Masako Houjouin (北条院 雅子,Hōjōin Masako): A mercenary who enters the competition with the selfish desire of winning the prize money and becoming fabulously rich. Although she practices no specific martial art, she is a master of using a number of weapons, which she keeps concealed until they are needed. Among her various arms are a knife, chain whip, guan dao, spiked mace, and a seemingly endless supply of grenades.

Hiyori Sakuragi (桜木 ひより,Sakuragi Hiyori): A shy, constantly depressed young woman who was forced to enter V.G. due to a number of mishaps that had occurred at the restaurant where she works. Although not a fighter by nature, she is capable of a staggering amount of strength when angered or upset.

Keiko Hatano (羽田野 恵子,Hatano Keiko): Nearly the polar opposite of Hiyori, Keiko is upbeat, cheerful, and outgoing. During a bout with Yuka, the latter expressed surprise that Keiko had enough power to apparently rival her own.

Yuu Asuka (飛鳥 優,Asuka Yū): The new main heroine/senshi. Yuu lives with her older brother in a restaurant which doubles as their own home (Her brother is the manager.). Upon an accident involving the restaurant she was in desperate need to find a way to fix the damage. She decided to risk it all by taking part of the Variable Geo tournament without letting her brother know. Yuu also appears in Giga's crossover games Xross Scramble and Otome Crisis.

Sanari Misumi (三角 沙奈理,Misumi Sanari): Yuu's long-time close friend, rival and classmate. A very energetic girl. Since their dojo days, Sanari has wished to have one real fight against Yuu, and thus picks a fight with Yuu every time they meet. Sanari did not work in a restaurant until she found out about Yuu's participation in the Variable Geo tournament and enters at the last minute.

Ayumi Okamoto (岡本 歩美,Okamoto Ayumi): A girl who is often very frightened and clumsy. Despite this, she becomes a capable fighter. Although she has no specific style, she copies other warriors' moves (it is rumored that she is trying to replicate moves of a legendary V.G. fighter).

Diane Ryan (ダイアン・ライアン,Daian Raian): Diane is a skilled martial artist from America. A girl with a rather bright personality and has a big appetite for food. Her motives for joining the tournament are unknown.

Kei Sagara (相楽 桂,Sagara Kei): A warrior skilled in aikido and carries the elemental power of lightning. She joins to test her strength.

Yui Zhenzhu (玉 真珠,Yui Chinjū): Zhenzhu hails from China and specializes in Chinese martial arts. She lives a very poor life with her old master and 18 brothers. Due to a past relationship, she has lost her faith in love. Like many before her, she has her eyes on the prize money.

Anna Fairgold (アンナ・フェアゴールド,Anna Feagōrudo): The current Variable Geo champion. A feared cold-blooded fighter who is sometimes driven insane. She fears the penalty because she had been through it once before.

There is a three-part animeOVA series based on the games that loosely follows the same plot as Advanced V.G., although with several facts changed: Miranda is dead and her spirit is seeking a new host body, the Hybrids do not exist, and the matches are ranked at different "levels" (Levels 1–5, with the implication that the penalties for losing differ, depending on the level of a given match), among other things. The voice actors for every character was changed for this series.